Thread: What to coat in epoxy?

What you coat in epoxy will be protected against rot and will have the paint last much much longer.

What you do not coat in epoxy will need to be rot resistant timber (ie, a tradional boat building timber) and will need to be painted but the paint won't last as long.

You do not 'need' to coat with epoxy, but it has been shown to make the paint and the boat last a lot longer.

Now, the cost, and believe me, I understand your concern. If using a roller, you actually don't use much epoxy. If slathering it on with a brush, yes you do but with a roller or a foam brush (and probably other techniques that I hope someone will tell us about), you actually don't use as much of the muck as you'd expect so, the cost and the weight factors are not as great as you fear. You don't need a thick coat of epoxy, just a waterproof one.

Richard

So do i take that to mean everything should be covered?

If i am for example covering the stringers do i coat them before or after I attach them?

Same with the ribs etc.

Do I coat the inside of the hull before or after I attach it?

i think it best to build the boat then coat it in epoxy encapsulating the whole thing in one go.

you mention about cost and weight but if you apply the epoxy with a roller as said by Daddles you will be surprised at how little you use, my 14ft Yellow tail only used 2.5 kilos of poxy to do the exterior with three coats applied wet on wet, in total including glueing, filling, filleting and coating i used 15 kilos of epoxy ( it think 1 kilo of that is still on my tools) so not that much extra weight on a 14 footer.
As for cost you will spend more on the up keep of the boat if you don't cover the whole thing in the stuff, so what little extra you pay now will save you a lot more expense in the future.

A plastic applicator, like the type used for body filler, works very well at smearing very thin sheets of epoxy on parts. I'm a squeegee man, myself, which works even better then the plastic applicator, because it's more flexible.

You should coat each piece separately, not after assembly. No bare wood should remain, including screw holes and notches.

You can pre-coat plywood sheets, which saves a good bit of time, leaving only the cut edges to coat once these are whittled down to boat parts.

The weight of epoxy coating isn't enough to worry about. On a TS-16 it might add all of 5 pounds to the total weight of the full up boat.

Do you need epoxy? Nope, you don't, particularly if you're not interested in the boat surviving very long with minimal care.

The one thing wooden boats can't tolerate for very long is neglect. Good epoxy encapsulation techniques will increase the amount of time you have before "issues" start appearing.

If your goal is a project that doesn't need a long life span, then skip the epoxy. If you'd like to hand this boat down to a son in a generation, then epoxy will help considerably.

Wooden boats were considered all but dead as a building medium in the late 1960's. A few "odd balls" were still building in wood, but metal and GRP had all but replaced wood in new construction.

This is about the time epoxy became something other then a miracle goo, the military used and the general public got their hands on it. Within a decade, it was found the properties of epoxy could not only save old wooden boats, but make new ones, lighter, stronger, faster to build and truly waterproof. Since then a huge wooden boat revival has occurred around the world and we haven't looked back since.

Back then, epoxy was used for everything, from fixing dieing derelicts to dentist fillings. We now have a much better understanding of how things work and why, so epoxy use has stabilized to a great degree.

Epoxy is even used to seal electrical connections on in body implants, like pace makers. Just about every industry you can think of has been revolutionized by epoxy. In the construction industry, we used to use anchor shields to hold lags into concrete, for supports, columns, etc. Now, a hole is drilled, some epoxy squirted in and the lag placed like it was in wet concrete. When dry, it's a whole lot stronger then an anchor shield and the fastener doesn't rust either.

On your little cruiser, you'll need in the neighborhood of 7 gallons of goo. More if you not especially neat about it, which is common among novice builders.

Log onto Michael's site (http://www.storerboatplans.com/) and look up using epoxy, applying epoxy, etc. He has a lot of useful information that you can use and dispels most of the rumors about the stuff too.

Thanks guys your help is great.

So with the ribs which are all shaped and I am about to glue together, should i encapsulate each component in epoxy and then glue them together (epoxy and temporary screws) or should I glue them together and then epoxy later?

And for odd shapes likle that what is the best way to apply the epoxy?

Originally Posted by hereselmo1

Thanks guys your help is great.

So with the ribs which are all shaped and I am about to glue together, should i encapsulate each component in epoxy and then glue them together (epoxy and temporary screws) or should I glue them together and then epoxy later?

And for odd shapes likle that what is the best way to apply the epoxy?

We're back into 'it depends' territory unfortunately ... and if you're me, much of it depends on your mood at the time too.

Truth is, it doesn't matter a whole lot - terms like 'easier' and 'harder' are relative, the boat is still buildable and sometimes it's better to buy some grief to save some grief later on.

The important things are:
- aim to have everything encapsulated, your bits of boat will last longer.
- try to glue raw timber to raw timber but if one half of a joint has been coated, make sure the surface is well sanded so the epoxy has something to grip to
- look at how hard it's going to be to sand the thing once it's in place ... but remember that you can do a lot of damage in tight areas with a Mouse Sander or something similar - there is very little you can't sand effectively with a bad attitude and a Mouse Sander.
- look at how hard it's going to be to glue things together if precoated or if covered with wet goop.
- vertical surfaces are easier to coat and sand when lying flat on something (an argument for coating them first)

Just take it easy. Boat building generally is NOT complicated or difficult, we just like to do that to ourselves because we're basically masochists. If you build your boat then coat things, you'll find areas that drive you mental when you try to sand them. You'll have other areas that'll do the reverse. When in doubt or confused, take the easier route ... provided it's a valid route.

Regardless of when you coat things or even if coat or not, you WILL spend a lot of time, head down bum up, ears ringing, back hurting and cursing that sodding sander. The nice part is, it comes to an end, you can slosh on some paint and then you're one up on most of the world because YOU built a BOAT

Richard

Originally Posted by Daddles

Regardless of when you coat things or even if coat or not, you WILL spend a lot of time, head down bum up, ears ringing, back hurting and cursing that sodding sander. The nice part is, it comes to an end, you can slosh on some paint and then you're one up on most of the world because YOU built a BOAT

Richard

and you're just about ready to start your next one

Howdy,

Racing boats have found that if they include the epoxy and still meet the minimum weight requirements for the class then the boats absorb less water and stay lighter during the season. Not mentioning the maintenance advantages.

Works for Herons, Tornados (when they were wood), Sabres (which end up about a kilo too heavy but don't get about 3kg heavier through the season - I used to supply the NSW state champion who built a new boat every season).

Up to you what you want to do. But if you want the maintenance advantage (now mentioning it) then every surface needs to be coated with a quality epoxy system.

Best wishes
MIK

Oh .. and roller distributes the epoxy in the most even way, saving epoxy and later effort. A squeegee can be useful on big flat surfaces. you will need a brush handy to get into little corners. And after doing the coats, sand the bit before it goes in. Then it is ready for varnish or paint.

MIK

Thanks Mik,

So just to clarify. I will be gluing my ribs together this week (epoxy and temporary screws). Should I coat each part before gluing or coat the while rib once it is all together? Also should I epoxy the stringers and chines etc. before attaching or after?

When laminating ribs, it's usually best to just coat the surfaces that will touch each other during the lamination. The reason is, they'll need some sanding and/or machining to even up the sides, need to be cut to length, etc. Coat them when they're ready to go in the boat, as finished pieces.

If you can, use a jig with wedges or clamps to hold your ribs, while the goo kicks off. This is far better then piercing each lamination in several places with a temporary screw, which will need it's hole filled later.

Boat building is all about problem solving. You'll do lots of it. Fore thought and planning is the goal, though very few novice builders show much of this on their first few builds.

PAR we are doing the Hartley with non-laminated timber ribs as per the plan, does that change anything?

I think they are cut out of plywood? and are part of the bulkheads that go into the boat.

PAR - to orient you ... 1960 style. ply bulkheads, stringers, multi chine construction. I think the bulkheads are clear of the ply skin as it just rests on the stringers (is that right hereselmo?)

If so make up all the bulkheads but before setting them up on the strongback do all your coating.

When you cut out the notches for the stringers that will reveal fresh timber for the stringers to glue into.

Makes a lot of sense to lie them all out on the flat and just do one side with the coats.

Then flip them over and do the same again. From memory the frames are a little fiddly and a squeegee might have a problem - so roller and back up brush.

The squeegee is the master at big flat areas.

Good chance to pump some info out of PAR .. he sounds like a real epoxy acolyte, but he is a very experienced builder and repairer in most wooden boat methods.

So ... PAR ... to do the ply panels for the skin of the boat ... would you be 100% happy with the inside face of the hull panels being precoated, dewaxed if necessary and sanded before going up on the frame? I am 98% happy with it and have built boats that way, but have not had enough long term experience to know how OK it is.

MIK

Originally Posted by Boatmik

I think they are cut out of plywood? and are part of the bulkheads that go into the boat.

PAR - to orient you ... 1960 style. ply bulkheads, stringers, multi chine construction. I think the bulkheads are clear of the ply skin as it just rests on the stringers (is that right hereselmo?)

If so make up all the bulkheads but before setting them up on the strongback do all your coating.

When you cut out the notches for the stringers that will reveal fresh timber for the stringers to glue into.

Makes a lot of sense to lie them all out on the flat and just do one side with the coats.

Then flip them over and do the same again. From memory the frames are a little fiddly and a squeegee might have a problem - so roller and back up brush.

The squeegee is the master at big flat areas.

Good chance to pump some info out of PAR .. he sounds like a real epoxy acolyte, but he is a very experienced builder and repairer in most wooden boat methods.

So ... PAR ... to do the ply panels for the skin of the boat ... would you be 100% happy with the inside face of the hull panels being precoated, dewaxed if necessary and sanded before going up on the frame? I am 98% happy with it and have built boats that way, but have not had enough long term experience to know how OK it is.

MIK

I am not sure what a bulkheas is exaclty and Wiki didnt really help but I think what you are calling bulkheads i have been calling ribs. They are designated to be cut out of 300x19 timber according to the plans, we are using meranti.

Other than that it sounds right Mik. So would you coat the stringers and chines before or after attaching them?